Structural reinforcement system having modular segmented characteristics

ABSTRACT

A modular segmented structural reinforcement system for use with closed forms or cavities defined with automotive vehicles having a plurality of modular segments designed to be secured within a defined portion of an automotive vehicle applications. An expandable or bonding material, such as an epoxy-based reinforcing foam or other sound absorption, damping, vibration reduction, or sealing material is disposed on at least a portion of the outer surface of each of the plurality of segments. Once the system is flexible fitted within the closed form or placed within a selected cavity of an automotive vehicle, the material expands and cures during an automobile assembly operation, bonding the reinforcement system to the segments. As a result, the reinforcement system provides enhanced load distribution over the vehicle frame without adding excessive weight and further serves to reduce noise and vibrational characteristics of the automotive vehicle.

FIELD OF THE INVENTION

The present invention relates generally to a structural reinforcementsystem for use in increasing the stiffness, strength, durability,sealing, and sound absorption/damping of different portions of a varietyof goods and products, such as furniture, commercial, industrial, andhousehold appliances, as well as land transportation vehicles, such asautomotive, aerospace, marine, and rail vehicles. More particularly, thepresent invention relates to segmented or modularly expandablestructurally reinforced closed forms, such as a hydroform structure orhydroform rail, which utilizes a plurality of segmented parts suitablefor flexible attachment and capable of providing a unitary structure forreinforcement of a desired area. Once attached as a whole, the segmentedportions maintain flexibility for movement and application into specificclosed form shapes while the exterior surface of each individual segmentor module can be coated with a material selected from a group consistingof a sealing material, or sound damping material, an anti-vibrationmaterial, a structurally reinforcing material, or other expandable andfoamable material to cross-link, structurally adhere, and reinforce theform when the material becomes chemically active and expands uponheating, self-heating, or is otherwise exposed to a heat or energysource.

BACKGROUND OF THE INVENTION

Traditionally, closed form or hydroforming techniques are used to drawand shape metal tubes. Conventional hydroforming techniques ofteninvolve two steps: (1) placing the desired bends in the tube and (2)forming the tube to the desired configuration. The second step of thisprocess usually requires placing a tubular member having an open bore ina mold and pinching off the ends of the tube. A pressurized liquid isthen injected into the open bore, causing the tube to stretch and expandout against the mold.

The manufacturing advantages of the hydroforming process is that itallows formation of relatively long tubular structures having a seamlessperimeter. This process eliminates the cost of welding, machining, orfastening operations often used to shape the part in the desiredconfiguration. As a result, a hydroform or closed form structure veryoften has a high length to diameter ratio. For instance, a hydroformstructure may have a length in excess of 15′ and a diameter ranging fromapproximately ¾″ to more than 12″. To this end, a further manufacturingprocess advantage of a hydroform structure is that it can exceed thelength of other tubular members, such as torsion bars or tubular bars,formed using other processes.

Additionally, hydroforming processing creates complex structural shapesthat typically include bends and contour changes. Often the number ofbends and contour changes in a hydroformed bar are greater and morecomplex than those found in torsion bars or other tubular structuresformed using different techniques. These shapes often have particularapplication in land transportation vehicles which require contourchanges to reflect vehicle styling and traditional automotivearchitecture in the form of automotive rails, pillars, and otherstructural members.

In addition, hydroform structures typically have a constant wallthickness prior to forming, and might develop strength differences atthe site of bends or changes in contour, as well as at certain locationsalong a long tubular section. Thus, it is often desirable to reinforceclosed form and hydroform sections to improve their structuralstiffness, strength, and durability, particularly in automotive vehicleapplications.

Traditional ways of reinforcing tubular structures such as hydroformsand other closed forms include sliding a metal sleeve inside the tubeand welding the reinforcing member in place. However, because thehydroform often includes one or more shapes or bends, or one or morechanges in contour and/or diameter, it is often difficult to insert thesleeve into the hydroform at the precise location of the weak portion.Other techniques include reinforcing the hydroform from the outside bywelding the sleeve onto the outside of the hydroform. However,hydroforms are often used in applications having very close tolerances,resulting in little or no clearance for an externally placed reinforcingmember. Accordingly, exterior reinforcements are often not as effectiveas interior reinforcements.

Additionally, in many operations the weight of the tubular member iscritical and must be kept low as possible. Thus, the use of an externalsleeve adds unwanted weight to the tubular assembly. Still further, thewelding operation tends to be labor intensive during the manufacturingprocess, time consuming and inexact, increasing the cost of forming thehydroform member and producing parts that have questionable reliability.Finally, these additional manufacturing steps and operations are oftencumbersome and difficult to integrate into a final vehicle manufacturingprocess in that additional tooling would need to be developed by themanufacturer and assembly plant resources, labor, maintenance, and spacewould need to be dedicated and expensed by the vehicle manufacturer.

Accordingly, there is a need in industry and manufacturing operationsfor system, device, and method for reinforcing the weak areas of closedforms and other hydroform tubes, such as a hydroform rail, withoutsignificantly increasing the weight and manufacturing complexity. Inparticular, there is a need for reinforcing a closed form or hydroform,which utilizes a plurality of segments or portions to achieve integratedreinforcement within the closed form since the contour or shape oftypical tubes do not allow for placement of single piece reinforcementmembers. In this regard, the present invention addresses and overcomesthe shortcomings found in the prior art by providing a multi-segmentreinforcement system having at least two segments or portions capable ofbeing modularly attached or otherwise engaged in segments within ahydroform that may then be fixed in location through the use of a thirdsegment or portion which serves as a locking, positioning, and retainingmember of the reinforcement system within the hydroform or other closedform. However, the plurality of modularly attached segments could alsobe locked, positioned, and retained within a hydroform through the useof retention means, such as a string, wire, or chain looped through eachof the segments which provides enough tension to retain each of thesegments in a desired position while the entire system (i.e. thesegments with an amount of bonding material disposed along at least aportion of each of the segments) is exposed and cured by the heattypically encountered in an automotive painting operation. Structuralreinforcement of the hydroform is achieved through activation by heat ofthe bonding material disposed along at least a portion of an outer orexterior surface of the plurality of segments or portions, such amaterial would typically expand when exposed to heat or other energysource and in doing so structurally adhere the segments or portions toeach other and the hydroform. Further, it is contemplated that thesystem would have greater flexibility to a range of applications byallowing each segment or portion of the plurality of segments to alsohave the capability of receiving a suitable amount of sealing material,sound absorption material, and/or an expandable material, or acombination thereof.

SUMMARY OF THE INVENTION

The present invention relates to methods and systems for reinforcing aclosed form or hydroform member. In one embodiment, the system includesa plurality of segments having a bonding material disposed over at leasta portion of the exterior or outer surface of the segments which may ormay not be expandable upon exposure to heat or other energy source. Theselected bonding material extends along at least a portion of theexterior surface of at least one segment which are then configured forplacement within a portion of a automotive vehicle to be reinforced.

In a particular preferred embodiment, the bonding material consists ofan expandable material which is generally and preferably aheat-activated epoxy-based resin having foamable characteristics uponactivation through the use of heat typically encountered in an e-coatprocess, paint oven, or other automotive painting operation. As thematerial is heated or otherwise exposed to an energy source in themanufacturing environment, it expands, cross-links, and structurallyadheres to adjacent surfaces. Preferred structural foam or expandablematerials are commercially available from L&L Products, Inc. of Romeo,Mich. under the designation L5204, L5206, L5207, L5208, or L5209.Generally speaking, these automotive vehicle applications may utilizetechnology and processes such as those disclosed in U.S. Pat. Nos.4,922,596, 4,978,562, 5,124,186, and 5,884,960 and commonly owned,co-pending U.S. application Ser. No. 09/502,686 filed Feb. 11, 2000,Ser. No. 09/524,961 filed Mar. 14, 2000, and particularly, 09/459,756filed Dec. 10, 1999, all of which are expressly incorporated byreference.

The system generally employs two or more segments or portions definedadapted for stiffening the structure to be reinforced and helping toredirect applied loads. In use, the segments are inserted into a closedform, such as a hydroformed tube, or simply placed or retained in acavity by retention means defined within portions of an automotivevehicle such as a pillar, rail, rocker, door assembly, or other framemember, with the heat activated bonding material serving as the loadtransferring and potentially energy absorbing medium. In a particularlypreferred embodiment, at least two of the segments are composed of apolymeric material, such as nylon, an injection molded nylon carrier, aninjection molded polymer, graphite, carbon, or a molded metal (such asaluminum, magnesium, and titanium, an alloy derived from the metals or ametallic foam derived from these metals or other metal foam) and is atleast partially coated with a bonding material on at least one of itssides, and in some instances on four or more sides. A preferred bondingmaterial is an epoxy-based resin, such as L5204, L5206, L5207, L5208 orL5209 structural foam commercially available from L & L Products, Inc.of Romeo, Mich. However, the present invention may further compriseretention means in an alternative form consisting of a third member,segment, or portion which serves to lock and position the at least firsttwo segments in place. This retention means could also utilize anadhesive material disposed along an outer surface of each of themembers, segments, or portions. Still further, the retention means,which serves to lock, position, and retain the plurality of members orsegments within the hydroform could also comprise locking means, such asa string, wire, or chain looped through each of the segments whichprovides enough tension to retain the plurality of segments in a desiredposition while the bonding material is activated in the e-coat orpainting operation. Once the bonding material is activated and cured, itis contemplated that the bonding material will structurally secure andretain the plurality of segments in the desired position within theportion of the vehicle to be reinforced.

In addition, it is contemplated that the plurality of segments couldcomprise a nylon or other polymeric material as set forth in commonlyowned U.S. Pat. No. 6,103,341, expressly incorporated by referenceherein. Still further, the segments adapted for stiffening the structureto be reinforced could comprise a stamped and formed cold-rolled steel,a stamped and formed high strength low alloy steel, a stamped and formedtransformation induced plasticity (TRIP) steel, a roll formed coldrolled steel, a roll formed high strength low alloy steel, or a rollformed transformation induced plasticity (TRIP) steel, as well as anelastomer, polyethylene, ethylene-vinyl acetate copolymer, plasticizedpolyvinyl chloride film, polyamide, polysulfone, or various olfeniccopolymer and terpolymer materials. Although the bonding material of thepresent invention does not need to be either heat-activatable orexpandable, a preferred material used in the present invention is anexpandable structural material. The choice of the material selected asthe bonding material will be dictated by performance requirements andeconomics of a specific application.

Additional bonding materials that could be utilized in the presentinvention include other materials which are suitable as acoustic media(i.e. sound absorbing, sound damping, or impacting NVH characteristics)and which may be heat activated which generally activate and expand tofill a desired cavity or occupy a desired space or function when exposedto temperatures typically encountered in automotive e-coat curing ovensand other paint operations ovens. Though other heat-activated materialsare possible, a preferred heat activated material is an expandable orflowable polymeric formulation, and preferably one that can activate tofoam, flow, adhere, or otherwise change states when exposed to theheating operation of a typical automotive assembly painting operation.For example, without limitation, in one embodiment, the polymeric foamis based on ethylene copolymer or terpolymer that may possess analpha-olefin. As a copolymer or terpolymer, the polymer is composed oftwo or three different monomers, i.e., small molecules with highchemical reactivity that are capable of linking up with similarmolecules. Examples of particularly preferred polymers include ethylenevinyl acetate, EPDM, or a mixture thereof. Without limitation, otherexamples of preferred foam formulation that are commercially availableinclude polymer-based material commercially available from L&L Products,Inc. of Romeo, Mich., under the designations as L-2105, L-2100, L-7005or L-2018, L-7101, L-7102, L-2411, L-2420, L4141, etc. and may compriseeither open or closed cell polymeric base material.

Further, it is contemplated that the plurality of segments or portionsof the present invention could employ a suitable amount of sealing,sound dampening, structural reinforcement, or acoustic material incombination upon different surfaces of the plurality of segments withinthe selected area to be reinforced to achieve specific points ofreinforcement, sealing, and/or sound damping depending upon theindividual needs or desirability of the specific application. Whenactivated through the application of heat, it is contemplated that asegment specific material will achieve not only structuralreinforcement, but may also assist in the reduction of vibration andnoise in the overall automotive body depending upon the characteristicsof the chosen bonding material. In this regard, the now reinforced area,closed form, or hydroform will have increased stiffness in thecross-members, which will shift the natural frequency, measured in hertzthat resonates through the automotive chassis and will reduce acoustictransmission and the ability to block or absorb noise through the use ofthe conjunctive acoustic, sealing, or sound damping product. Byincreasing the stiffness and rigidity of the cross-members, the noiseand frequency of the overall engine ride vibration that occurs from theoperation of the vehicle can be reduced since a shift in frequency ofnoise and vibration will allow resonance through the chassis. Althoughthe use of such sealing, damping, and vibration reducing materials ormedia can be utilized instead of, or in conjunction with, the structuralexpandable material on the individual segments of the present invention,the preferred embodiment of the structural reinforcement system of thepresent invention utilizes a bonding material consisting of astructurally reinforcing expandable material. Use of acoustic materialsin conjunction with structural may provide additional structuralimprovement but primarily would be incorporated to improve NVHcharacteristics.

It is also contemplated that the material of the present invention couldbe delivered and placed into contact with the segments through a varietyof delivery systems which include, but are not limited to, a mechanicalsnap fit assembly, extrusion techniques commonly known in the art aswell as a mini-applicator technique as in accordance with the teachingsof commonly owned U.S. Pat. No. 5,358,397 (“Apparatus For ExtrudingFlowable Materials”), hereby expressly incorporated by reference. Inthis non-limiting embodiment, the material is at least partially coatedwith heat-activated material that could be structural, sealing,dampening, or acoustic in nature. This preferably heat activatedmaterial can be snap-fit onto the chosen surface or substrate; placedinto beads or pellets for placement along the chosen substrate or memberby means of extrusion, placed along the substrate through the use ofbaffle technology, die-cut according to teachings that are well known inthe art, utilize pumpable application systems which could include theuse of a baffle and bladder system, as well as sprayable applications.

In another embodiment, the plurality of segments are composed of aninjection molded nylon and provided with a suitable amount of bondingmaterial or load transfer medium molded onto its sides in at least onelocation defining a portion wherein each portion is smaller in diameterthan a corresponding insertable opening in the form or tube to enableplacement within a cavity defined within an automotive vehicle, such asportions of a hydroform tube, hydroform rail, or other area or substratefound in an automotive vehicle which could benefit from the structuralreinforcement characteristics found in the present invention. In thisembodiment a plurality of modularly attachable segments or portions areutilized to provide an integrated member, having flexiblecharacteristics relative to one another similar to the movements of anaccordian, for installation within a hydrofromed rail or other area of avehicle that would benefit from structural reinforcement. For example, afirst segment or portion corresponds to, and is insertably attached toan opening located within the hydroform tube or hydrofrom rail section.A second segment or portion is modularly attachable or slideably engagedand affixed to a surface of the first segment or portion. A thirdsegment or portion, and a plurality of portions thereafter, is thenmodularly attached or slideably engaged and affixed to a surface of thepreceding plurality of segments. It is contemplated that the modularlyattached or slideably engaged plurality of segments will still provide acertain degree of freedom or flexibility whereby the plurality ofsegments can flex and be shaped to fit within the contours or geometricrequirements of the area to be structurally reinforced. A fixed lockingmember or retention means, such as a heal and toe feature, is thenutilized to place or fix the plurality of segments or portions togetherwithin the area to be reinforced thereby retaining the segments.Further, the locking member could comprise tension means, such as astring, wire, chain, or cable retaining the plurality of segments withthe bonding material on the exterior surface of the segments in adesired position while the system undergoes baking in an automotivepainting operation. The bonding material is activated to accomplishexpansion through the application of heat typically encountered in anautomotive e-coat oven or other painting operation oven in the spacedefined between the plurality of segments or portions and the walls ofthe cavity selected for reinforcement. The resulting structure includesthe wall structure of the hydroform tube or cavity joined to theplurality of segments with the aid of the now activated bondingmaterial. It is contemplated that each individual segment or portioncould be configured for application of a bonding material, expandablematerial, or sealing material applied in a variety of patterns, shapes,and thicknesses to accommodate the particular size, shape, anddimensions of the cavity corresponding to the chosen form or vehicleapplication.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and inventive aspects of the present invention will becomemore apparent upon reading the following detailed description, claimsand drawings, of which the following is a brief description:

FIG. 1 is a perspective view of a modular segmented structuralreinforcement system in accordance with the teachings of the presentinvention.

FIG. 2 is an exploded section view of a portion of a hydroform describedin FIG. 1, showing the position of the plurality of modular segments andthe expandable material in the uncured state.

FIG. 3 is a cutaway sectional view of a modular segmented structuralreinforcement system in accordance with the teachings of the presentinvention placed within a hydroform in accordance with the teachings ofthe present invention prior to activation of the expandable material.

FIG. 4 is a cutaway sectional view of a modular segmented structuralreinforcement system in accordance with the teachings of the presentinvention placed within a hydroform in accordance with the teachings ofthe present invention after activation of the expandable material.

FIG. 5 is a cutaway sectional view of an alternative embodiment of themodular segmented structural reinforcement system placed withinautomotive vehicle pillar without the use of a hydroform in accordancewith the teachings of the present invention

FIG. 6 is a partial perspective view of an alternative embodiment of themodular segmented structural reinforcement system in accordance with theteachings of the present invention showing a plurality of modularsegments held together by attachment means which permit the flexing ofat least one modular segment relative to one another for placement ineither a hydroform or directly to portions of an automotive vehicle.

FIG. 7 is a perspective view of a an alternative embodiment of themodular segmented structural reinforcement system in accordance with theteachings of the present invention showing a plurality of modularsegments held together by attachment means comprising a traditional balland socket assembly which permits the flexing of at least one modularsegment relative to one another for placement in either a hydroform ordirectly to portions of an automotive vehicle.

FIG. 8 is a perspective view of a an alternative embodiment of themodular segmented structural reinforcement system in accordance with theteachings of the present invention showing a plurality of modularsegments held together by attachment means comprising a hitch snapassembly which permits the flexing of at least one modular segmentrelative to one another for placement in either a hydroform or directlyto portions of an automotive vehicle.

FIG. 9 is a perspective view of a an alternative embodiment of themodular segmented structural reinforcement system in accordance with theteachings of the present invention showing a plurality of modularsegments held together by attachment means comprising a chain assemblywhich permits the flexing of at least one modular segment relative toone another for placement in either a hydroform or directly to portionsof an automotive vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a modular segmented reinforcement system 10 formed inaccordance with the teachings of the present invention. The modularsegmented reinforcement system 10 may impart increased strength,stiffness, sealing, sound absorption, or durability to a structuralmember or other portion of an automotive vehicle, and, thus, may be usedin a variety of applications for different products. For instance, themodular segmented reinforcement system 10 may be used as part of theframe or rail system for automobiles and building structures. Otherapplications of the system 10 include furniture items, appliances, andaerospace, marine, rail, and automotive vehicles.

In a preferred embodiment, as in FIG. 2, the present invention comprisesat least two segments 12 composed of an injection molded polymer. Thesegments 12 are provided with a suitable amount of a bonding material 14molded or disposed along the exterior surface or sides of the segments12 thereby defining a plurality of segmented portions 16 wherein eachportion 16 is smaller in diameter than a corresponding insertableopening in the form or tube 18. The segments 12 are modular and arecapable of being shaped and sized to fit a variety of closed formapplications, such as a hydroform rail. However, it is contemplated thatthe segments 12 can be of any geometric size, shape, and dimensioncorresponding to the selected area to be reinforced or damped. Theplurality of segments 12 are suitable for placement within a cavitydefined within an automotive vehicle, such as portions of a hydrofromframe rail, tube section, pillar, rocker, gate, or other area orsubstrate found in an automotive vehicle which could benefit from thestructural reinforcement characteristics found in the present invention.In this embodiment, a first modular segment or portion 20 correspondsto, and is insertably attached to an opening located within a hydroformrail section or other area to be structurally reinforced, such as acavity found in an automotive vehicle. A second modular segment orportion 22 is slideably engaged and affixed to a portion of the firstmodular segment 20. The present invention provides for a plurality ofsuccessive modular segments or portions that can be slideably engagedand affixed to one another thereby forming a unitary reinforcementsystem for placement within the hydroform rail or tube 18 or othercavity selected for structural reinforcement. It is contemplated thatthe plurality of modular segments or portions is both flexible andshapeable to the contour and shape of the desired closed form orhydroform, as well as the geometric configuration of other areasselected for reinforcement. In other words, it is contemplated that eachof the plurality of segments 12 are flexible relative to each other sothat the system 10 can be substantially formed to follow the contours ofthe tube 18 or other chosen portion of an automotive vehicle with orwithout the use of a tube 18. Accordingly, once a first modular segmentor portion 20, consisting of a segment with the bonding material 14placed along the segment, is positioned and slideably engaged with asecond modular segment or portion 22, the now unitary first 20 andsecond 22 modular segments or portions provide a degree of movement orflexibility relative to one another thereby providing reinforcementalong the contours and specific shape of the hydroform which cannot beachieved through injection molding, sheet metal applications, or otherprocesses disclosed in the prior art. A locking or retaining member 24,which can comprise an additional segment, portion, or retention means orassembly, is then utilized to fixedly bridge the at least first 20 andsecond 22 segments or portions together. Although a ball and socketfeature well known in the art is shown as the locking member or means inFIG. 7, it is contemplated that locking member 24 could be shaped andconfigured to position and retain any number of a plurality of segmentsor portions and that the present invention simply discloses at least twosegments or portions for illustrative purposes only and should not belimited to the number of modular segments and corresponding flexibleshapes that may be desirable in a variety of applications. In addition,the locking member or retention means 24 could comprise a traditionalstring, wire, or cable looped or tied through each of the plurality ofmodular segments thereby retaining the modular segments in a desiredposition or simply to achieve retention of the segments 12 or portions16 in a flexible or accordion-like state whereby each segment 12 orportion 16 could move relative to each other for placement within adefined shape or cavity of an automotive vehicle which does not utilizea tube or form, as shown in FIGS. 6-9. In this regard, the bondingmaterial 14 disposed along the exterior surface or sides of the segments12, once activated to accomplish expansion through the application ofheat typically encountered in an automotive e-coat oven or other heatingoperation, positions and locks the plurality of segments in space alongthe walls of the tube or portion of the automotive vehicle defining thecavity. The resulting structure may include the wall structure joined tothe plurality of segments with the aid of the activated material 14.

It is contemplated that the material 14 could be applied to the exteriorsurface or sides of each of the plurality of modular segments in avariety of patterns, shapes, and thicknesses to accommodate theparticular size, shape, and dimensions of the cavity corresponding tothe chosen form or vehicle application. In addition, each of theplurality of segments could provide a versatile function depending uponthe chosen hydroform application. For example, the bonding material 14could comprise a sealing material, a sound absorption material, adamping material, or a structural reinforcement material. Thesedifferent variations of the bonding material 14 could be placed alone orin combination on different segments or different portions of segmentsto achieve a desired localized result along the tube 18, such aslocalized structural reinforcement, localized sealing, and/or localizedsound damping. The material 14 is activated to accomplish expansionthrough the application of heat typically encountered in an automotivee-coat oven or other heating operation in the space defined between theplurality of segments and the walls of the hydroform tube or the portionof the vehicle defining the cavity. The resulting structure includes thewall structure of the hydroform tube or cavity joined to the pluralityof segments with the aid of the chosen material 14.

In one embodiment, at least two of the modular segments and, as shown,the first 20 and second 22 segments are nested together within thehydroform tube 18 with each having an application of the bondingmaterial 14. A locking member 24, which is suitable for receiving anamount of bonding material 14 along one or more of its exterior or outersurfaces, is then either placed into contact with the first 20 andsecond 22 segments or insertably engaged through the hydroform tube 18to serve as a locking and positioning member of the reinforcementsystem. Structural reinforcement of the hydroform tube 18 is achievedthrough activation by heat or some other activation stimulus or sourceof energy applied to the material 14 disposed along at least the first20 and second 22 modular segments wherein the material 14 may expand andwill structurally adhere the at least two modular segments 20 and 22,and the locking member 24 to each other and the hydroform tube 18.

In a preferred embodiment, it is contemplated that the bonding material14 comprises a structural foam, which is more preferably heat-activatedand expands and cures upon heating, typically accomplished by gasrelease foaming coupled with a cross-linking chemical reaction. Thisstructural foam is generally applied to the segments 12 in a solid orsemi-solid state. The structural foam may be applied to the outersurface of the segments 12 in a fluid state using commonly knownmanufacturing techniques, wherein the structural foam is heated to atemperature that permits the structural foam to flow slightly to aid insubstrate wetting. Upon curing the structural foam hardens and adheresto the outer surface of the segment 12. Alternatively, the structuralfoam may be applied to the segments 12 as precast pellets, which areheated slightly to permit the pellets to bond to the outer surface ofthe segments 12. At this stage, the structural foam is heated justenough to cause the structural foam to flow slightly, but not enough tocause the structural foam to thermally expand. Additionally, thestructural foam may also be applied by heat bonding/thermoforming or byco-extrusion. Note that other stimuli activated materials capable ofbonding can be used, such as, without limitation, an encapsulatedmixture of materials that, when activated by temperature, pressure,chemically, or other by other ambient conditions, will become chemicallyactive. To this end, one aspect of the present invention is tofacilitate a streamlined manufacturing process whereby the bondingmaterial 14 can be placed along the segments 12 in a desiredconfiguration and inserted within the closed form or hydroform at apoint before final assembly of the vehicle.

The bonding material 14 that may have foamable characteristics isgenerally an epoxy-based material, but may include an ethylene copolymeror terpolymer, such as with an alpha-olefin. As a copolymer orterpolymer, the molecule is composed of two or three different monomers,i.e., small molecules with high chemical reactivity that are capable oflinking up with similar molecules. A number of epoxy-based structuralreinforcing foams are known in the art and may also be used to producethe bonding material 14 of the present invention. A typical structuralfoam includes a polymeric base material, such as an epoxy resin orethylene-based polymer which, when compounded with appropriateingredients (typically a blowing agent and perhaps a curing agent andfiller), typically expands and cures in a reliable and predictablemanner upon the application of heat or another activation stimulus. Theresulting material has a low density and sufficient stiffness to impartdesired rigidity to a supported article. From a chemical standpoint fora thermally-activated material, the structural foam is usually initiallyprocessed as a thermoplastic material before curing. After curing, thestructural foam typically becomes a thermoset material that is fixed andincapable of flowing.

An example of a preferred structural foam formulation is an epoxy-basedmaterial that may include polymer modificis such as an ethylenecopolymer or terpolymer that is commercially available from L&LProducts, Inc. of Romeo, Mich., under the designations L5206, L5207,L5208 and L5209. One advantage of the preferred structural foammaterials over prior art materials is the preferred materials can beprocessed in several ways. Possible processing techniques for thepreferred materials include injection molding, extrusion or extrusionwith a mini-applicator extruder. This enables the creation of partdesigns that exceed the capability of most prior art materials.

While the preferred materials for fabricating the bonding material 14have been disclosed, the material 14 can be formed of other materialsprovided that the material selected is heat-activated or otherwiseactivated by an ambient condition (e.g. moisture, pressure, time or thelike) and expands in a predictable and reliable manner under appropriateconditions for the selected application. One such material is the epoxybased resin disclosed in commonly-assigned U.S. Pat. No. 6,131,897 forStructural Reinforcements, which is incorporated herein by reference.Some other possible materials include, but are not limited to,polyolefin materials, copolymers and terpolymers with at least onemonomer type an alpha-olefin, phenol/formaldehyde materials, phenoxymaterials, polyurethane materials with high glass transitiontemperatures, and mixtures or composites that may include even metallicfoams such as an aluminum foam composition. See also, U.S. Pat. Nos.5,766,719; 5,755,486; 5,575,526; 5,932,680 (incorporated herein byreference). In general, the desired characteristics of the medium 14include high stiffness, high strength, high glass transition temperature(typically greater than 70 degrees Celsius), and good adhesionretention, particularly in the presence of corrosive or high humidityenvironments. Still further, it is contemplated that the material 14 ofthe present invention could comprise a sealant, sound absorptionmaterial, or a damping material used alone, or in combination with, astructural foam disposed along the plurality of segments or portions ofthe plurality of segments to effectuate localized structuralreinforcement, sealing, and/or sound absorption along specific chosenzones of the tube 18.

In applications where a heat activated, thermally expanding material isemployed, an important consideration involved with the selection andformulation of the material comprising the structural foam is thetemperature at which a material reaction or expansion, and possiblycuring, will take place. For instance, in most applications, it isundesirable for the material to be active at room temperature orotherwise at the ambient temperature in a production line environment.More typically, the structural foam becomes reactive at higherprocessing temperatures, such as those encountered in an automobileassembly plant, when the foam is processed along with the automobilecomponents at elevated temperatures or at higher applied energy levels.While temperatures encountered in an automobile assembly body shop ovensmay be in the range of 148.89° C. to 204.44° C. (300° F. to 400° F.),and paint shop oven temps are commonly about 93.33° C. (215° F.) orhigher. If needed, blowing agents activators can be incorporated intothe composition to cause expansion at different temperatures outside theabove ranges.

Generally, prior art expandable acoustic foams have a range of expansionranging from approximately 100 to over 1000 percent. The level ofexpansion of the bonding medium 14 may be increased to as high as 1500percent or more, but is typically between 0% and 300%. In general,higher expansion will produce materials with lower strength andstiffness.

The modular segmented reinforcement system 10 disclosed in the presentinvention may be used in a variety of applications where structuralreinforcement is desired. The modular segmented system 10 has particularapplication in those instances where the overall weight of the structurebeing reinforced is a critical factor. For instance, the system 10 maybe used to increase the structural strength of aircraft frames, marinevehicles, automobile frames, building structures or other similarobjects. In the preferred embodiment disclosed, the system 10 is used aspart of an automobile frame to reinforce selected areas of theautomobile frame or rails, and may also be utilized in conjunction withrockers, cross-members, chassis engine cradles, radiator/rad supports,and door impact bars in automotive vehicles with or without the use of ahydroform.

The system 10 is suitable for placement within a vehicle pillar, rail,rocker, or frame portion of an automobile frame assembly. At least twosegments 12, and preferably a plurality of segments shaped to thecontour of the chosen cavity or space defined in the automotive vehicle,are composed of an injection molded polymer (or other material (e.g.,metal) or composite) provided with a suitable amount of a load transferor bonding material 14 molded or disposed along the exterior surface orsides of the segments 12 thereby defining a plurality of portions 16suitable for placement within a cavity defined within an automotivevehicle, such as portions of a hydroform tube section or other area orsubstrate found in an automotive vehicle which could benefit from thestructural reinforcement characteristics found in the present invention.In this embodiment, it will be appreciated that the system 10 of thepresent invention may be used to reinforce other areas of an automobileframe or rocker assembly and the number of segments 12 and placement ofthe bonding material 14 along the segments 12 would be dictated by theshape and desired application. As shown in FIG. 6, it is contemplatedthat the members would be flexible nested together by use of the lockingor retention means 24 such as a string, clip, chain, cable, ball andsocket assembly, or hitch-snap assembly which retains the segments 12but still allows flexible movement relative to one another whereby apredetermined number of segments 12 can be utilized and shaped to fitwithin a defined shape and placement of an automotive vehicleapplication to provide structural reinforcement of the application afteractivation of the bonding material 14.

Though other heat activated materials are possible, a preferred bondingmaterial 14 is an expandable polymeric material, and preferably one thatis foamable. A particularly preferred material is an epoxy-basedstructural foam. For example, without limitation, in one embodiment, thestructural foam is an epoxy-based material that may include an ethylenecopolymer or terpolymer. A number of epoxy-based structural reinforcingfoams are known in the art and may also be used to produce thestructural foam. A typical structural foam includes a polymeric basematerial, such as an epoxy resin or ethylene-based polymer which, whencompounded with appropriate ingredients (typically a blowing and curingagent), expands and cures in a reliable and predicable manner upon theapplication of heat or the occurrence of a particular ambient condition.From a chemical standpoint for a thermally-activated material, thestructural foam is usually initially processed as a flowablethermoplastic material before curing. It will cross-link upon curing,which makes the material incapable of further flow.

Some other possible materials include, but are not limited to,polyolefin materials, copolymers and terpolymers with at least onemonomer type an alpha-olefin, phenol/formaldehyde materials, phenoxymaterials, and polyurethane. See also, U.S. Pat. Nos. 5,266,133;5,766,719; 5,755,486; 5,575,526; 5,932,680; and WO 00/27920 (PCT/US99/24795) (all of which are expressly incorporated by reference). Ingeneral, the desired characteristics of the resulting material includerelatively high glass transition point, and good environmentaldegradation resistance properties. In this manner, the material does notgenerally interfere with the materials systems employed by automobilemanufacturers. Moreover, it will withstand the processing conditionstypically encountered in the manufacture of a vehicle, such as thee-coat priming, cleaning and degreasing and other coating processes, aswell as the painting operations encountered in final vehicle assembly.

In another embodiment, the material 14 is provided in an encapsulated orpartially encapsulated form, which may comprise a pellet, which includesan expandable foamable material, encapsulated or partially encapsulatedin an adhesive shell, which could then be attached to the members 12 ina desired configuration. An example of one such system is disclosed incommonly owned U.S. Pat. No. 6,422,575 for an Expandable Pre-FormedPlug, hereby incorporated by reference. In addition, as discussedpreviously, preformed patterns may also be employed such as those madeby extruding a sheet (having a flat or contoured surface) and then diecutting it according to a predetermined configuration.

In addition, the present invention provides and discloses retentionmeans for retaining the plurality of modular segmented members inposition for placement directly within a selected cavity of anautomotive vehicle. The retention means can consist of a number ofalternative embodiments or assemblies that may be utilized as retentionmeans for the plurality of modular segmented members. Namely, theretention means may comprise, but is not limited to: a traditional balland socket assembly as shown in FIG. 7, a hitch-snap assembly as shownin FIG. 8, and a chain assembly as shown in FIG. 9.

The skilled artisan will appreciate that the system may be employed incombination with or as a component of a conventional sound blockingbaffle, or a vehicle structural reinforcement system, such as isdisclosed in commonly owned co-pending U.S. application Ser. Nos.09/524,961 or 09/502,686 (hereby incorporated by reference).

A number of advantages are realized in accordance with the presentinvention, including, but not limited to, the ability to manufacture astructural reinforcement system for use in a hydroform or other closedform for delivery and assembly at a vehicle assembly plant without theneed for application of pumpable products, wet chemical products, andmultiple sets of tools, such as for other prior art.

The preferred embodiment of the present invention has been disclosed. Aperson of ordinary skill in the art would realize however, that certainmodifications would come within the teachings of this invention.Therefore, the following claims should be studied to determine the truescope and content of the invention.

1. A method of reinforcing a structure of an automotive vehicle,comprising: providing a structure of an automotive vehicle, thestructure having a plurality of walls defining a cavity; locating aplurality of modular segments within the cavity wherein the plurality ofmodular segments includes a first segment, a second segment and a thirdsegment, both the first segment and the second segment having expandablematerial disposed upon outer surfaces thereof and wherein each of thesecond segment and the third segment, only after insertion within thecavity, engages another of the plurality of segments that is alreadywithin the cavity; activating the expandable material of the firstsegment to expand, contact and adhere to the second segment; andactivating the expandable material of the second segment to expand,contact and adhere to the walls defining the cavity of the structure ofthe automotive vehicle.
 2. A method as in claim 1 wherein each segmentof the plurality of the segments is shaped to the contours of thecavity.
 3. A method as in claim 1 wherein a singular retaining member isdisposed through each of the plurality of segments during the locatingstep.
 4. A method as in claim 1 wherein the third segment includes anannular outer surface upon which the expandable material is disposed. 5.A method as in claim 4 wherein the expandable material, upon expansion,adheres to the walls of the structure and forms the plurality ofsegments into a unitary structure.
 6. A method as in claim 1 whereinsaid expandable material is an expandable foam that is generally free oftack to the touch.
 7. A method as in claim 1 the structure beingselected from a pillar, a rail or a combination thereof.
 8. A method asin claim 1 wherein each segment of the plurality of segments includes afirst portion and a second portion and the plurality of modular segmentsare maintained in an accordion-like state with the first portion of thefirst segment of the plurality of modular segments located at leastpartially within a cavity defined in the second portion of the secondsegment of the plurality of modular segments.
 9. A method of reinforcinga structure of an automotive vehicle, comprising: providing a structureof an automotive vehicle, the structure having a plurality of wallsdefining a cavity; locating a first segment of a plurality of modularsegments within the cavity; slideably engaging a second segment of theplurality of modular segments with the first segment of the plurality ofmodular segments, both the first segment and second segment havingexpandable material disposed upon their outer surfaces; activating theexpandable material of the first segment to expand, contact and adhereto the second segment; and activating the expandable material of thesecond segment to expand, contact and adhere to the walls defining thecavity of the structure of the automotive vehicle; wherein a singularretaining member is disposed through each of the plurality of segmentsduring the slideably engaging step.
 10. A method as in claim 9 furthercomprising: slideably engaging a third segment of the plurality ofmodular segments with the second segment of the plurality of modularsegments.
 11. A method as in claim 9 wherein each segment of theplurality of the segments is shaped to the contours of the cavity.
 12. Amethod as in claim 9 wherein the outer surfaces are annular and theexpandable material, upon expansion, adheres to the walls of thestructure and forms the plurality of segments into a unitary structure.13. A method as in claim 9 wherein said expandable material is anexpandable foam that is generally free of tack to the touch.
 14. Amethod as in claim 9 wherein each segment of the plurality of segmentsincludes a first portion and a second portion and the plurality ofmodular segments are maintained in an accordion-like state with thefirst portion of a first segment of the plurality of modular segmentslocated at least partially within a cavity defined in the second portionof a second segment of the plurality of modular segments.
 15. A methodof reinforcing a structure of an automotive vehicle, comprising:providing a structure of an automotive vehicle, the structure having aplurality of walls defining a cavity; locating a first segment of aplurality of modular segments within the cavity; slideably engaging asecond segment of the plurality of modular segments with the firstsegment of the plurality of modular segments, both the first segment andsecond segment having expandable material disposed upon their outersurfaces, wherein: i) the first segment of the plurality of segmentsflexibly nests with the second segment of the plurality of segments suchthat the first segment and second segment can make accordion motionsrelative to each other; and ii) each segment of the plurality of modularsegments successively engages another of the plurality of modularsegments, the plurality of modular segments including the first segment,the second segment and a third segment; activating the expandablematerial of the first segment to expand, contact and adhere to thesecond segment; and activating the expandable material of the secondsegment to expand, contact and adhere to the walls defining the cavityof the structure of the automotive vehicle.
 16. A method as in claim 15wherein each segment of the plurality of the segments is shaped to thecontours of the cavity.
 17. A method as in claim 15 wherein thestructure is a hydroform tube.
 18. A method as in claim 15 wherein theexpandable material, upon expansion, adheres to the walls of thestructure and forms the plurality of segments into a unitary structure.19. A method as in claim 15 wherein said expandable material is anexpandable foam that is generally free of tack to the touch.